Ron Perla working on slab above Alta village, 1968. Credit: Charles Bradley, Montana State University

Recipient of the 2024 Distinguished Alumni award from the Department of Atmospheric Sciences, Perla graduated in 1971 with his PhD from the University of Utah in meteorology. As a snow scientist, he conducted research into avalanches and is well-known for discovering “the thirty-degree threshold,” where slopes of thirty degrees or more are much likelier to cause avalanches.

Perla worked at Alta Ski Resort as a member of the ski patrol and in 1966 became a part-time snow ranger and part-time research assistant at the U.S. Forest Service (USFS) Alta Avalanche Study Center. As a research assistant to Ed LaChapelle, Perla researched slab properties, factors that contribute to an avalanche and rescue methods, among other things.

Early in the morning and during intense storms, snow rangers blast the mountain to reduce the risk of avalanches. Between these times, Ed LaChapelle allowed Perla to take classes at the U. From 1967 to 1971 Perla commuted between Alta and the university. He split his time between snow rangering and his PhD program supervised by Professor Shih-Kung Kao and included classes in meteorology and applied mechanics. These classes are fundamental disciplines for avalanche research.

Perla’s advisor, along with the Department of Meteorology's chair Don Dickson, understood the unique combination of university study and avalanche study. Kao was a world-class specialist in atmospheric dynamics, turbulence and diffusion while Dickson was a highly decorated World War II pilot with hands-on meteorology experience. He helped Perla obtain a research grant from the Rockefeller Foundation and arranged for the donation of an old Alta ski lifts building which was turned into a mountain meteorology lab.

Models of moving avalanches

Perla has also extensively researched snow structure as well as models of moving avalanches. His current research involves quasi-three-dimensional modeling of the internal structure of a moving avalanche, from start to stop and has modeled moving snow in many different ways. His first model (1980) followed the mass-center of moving snow, and in 1984 his model assumed the avalanche as a collection of starting particles. The current model assumes the avalanche consists of snow parcels moving turbulently in three layers.

Ron Perla, U.S. Forest Service, 1968.

Along with his research, Perla has spent a lifetime in the snow. An avid skier and mountaineer, he partnered with Tom Spencer (U alum in mathematics) in 1961 for the first ascent of Emperor Ridge on Mt. Robson, the highest point in the Canadian Rockies. He also established a new route on the north face of the Grand Teton in Wyoming and a first ascent of the popular “Open Book” route on Lone Peak in the Wasatch Mountains.

“In 1967, I was working as a USFS Snow Ranger near the top of Mt. Baldy,” Perla says. “The cornice broke off prematurely, and I fell into a Baldy chute. The cornice blocks triggered a large avalanche. I was tumbled around with no chance of 'swimming,' and somehow I missed all of the rocks. Just before I lost consciousness under the snow, I managed to thrust an arm up to the surface. I was found quickly.”

Collective consciousness

Perla is an honorary member of the American Avalanche Association as well as a member of multiple different snow and ice committees, such as the Snow, Ice, and Permafrost committee for the American Geophysical Union.

After earning his PhD at the U, Perla moved to Fort Collins, Colorado as a research meteorologist for the USFS. In 1974, he moved to Alberta, Canada to work for the National Hydrology Research Institute. He has remained in Alberta since.

Perla is a significant reason why we understand snow science and avalanches and why backcountry education has improved to help keep those who recreate in areas with snowfall — skiers, mountaineers, snowshoers and ice climbers — safe.

“Despite the enormous increase in backcountry use, despite increasing behavior to ski and ride lines we could never imagine in the 1960s, avalanche fatalities are not increasing to match those trends,” Perla says in an interview with Wildsnow. "Surely, associations, centers, websites, and educators, in general, are responding to match those trends. Surely it’s also because today’s risk-takers are increasingly more skillful backcountry skiers, riders, and [,as in Perla's harrowing experience on Mt. Baldly,] escape artists."

He continues, adding that "[e]quipment is improving. ...But there’s something else: call it collective consciousness in the backcountry. An increasing number of backcountry users correlates with increasing observations and tests. Thus, safety can be enhanced by numbers if there is increased communication... ."

You can read Ron Perla's interview with Wildsnow here.